An electrical module comprises a first wall with a plug interface, wherein the plug interface includes a plurality of plug pins and a collar surrounding the plug pins, the collar having an envelope surface. A second wall is provided with a socket interface, wherein the socket interface includes a socket tip exhibiting a plurality of socket holes adapted to receive plug pins of an adjacent electrical module. The socket tip is surrounded by a socket cavity provided in the second wall and adapted to receive a collar of an adjacent electrical module. The plug interface is adapted to be connected to a socket interface of a corresponding electrical module and the socket interface is adapted to be connected to a plug interface of a corresponding electrical module. By providing a curved slope on the envelop surface of the collar, advantageous connection properties are achieved.